Drive line apparatus

ABSTRACT

A drive line apparatus has a pair of tubular shafts configured to fit telescopically. The outer shaft has internal splines and the inner shaft has outer splines so that the shafts rotate in unison. Each of the outer and inner shaft has one partially closed end for coupling to an individual joint, wherein the joint connected to the partially closed end of the inner shaft is disposed within the inner shaft for further reducing the length of the drive line apparatus.

[0001] This application claims benefit of U.S. Provisional Application No. 60/191,162 filed Mar. 22, 2000.

FIELD OF THE INVENTION

[0002] The invention relates to a drive line apparatus for use where there is limited space between a driving member and a driven member.

BACKGROUND OF THE INVENTION

[0003] The drive line shaft connects the transmission output to the differential at the rear wheel on rear drive vehicles. The rotary motion of the transmission output shaft is carried to the differential and from there to the wheel. The drive line shaft must change in length and angle as the wheels move up and down. To allow for these two variations, two or more universal joints and a slip joint are required. The universal joint accommodates a change in the drive angle. The slip joint accommodates a change in the length of the drive line.

[0004] In the conventional drive line shaft, the slip joint has outside splines on one shaft and matching internal lines on a mating hollow shaft. The splines cause the two shafts to rotate together and to permit the two to move endwise in relation to each other. This allows changes in the length of the propeller shaft as the rear axles move toward or away from the vehicle frame.

[0005] Some vehicles, such as busses, have the engine mounted at the rear. Because of the limited space available, short shafts and universal joints carry the engine power to the rear wheels. It would be desirable to provide the shortest transmission shaft possible without sacrificing the strength of the shaft to support bearing stresses.

SUMMARY OF THE INVENTION

[0006] It is the intent of the invention to address the aforementioned concerns. In one aspect of the invention, a drive line apparatus is provided for connection between an output portion of a driving member and an input portion of a driven member wherein the output portion and input portion are each connectable to a universal joint, and the drive line apparatus comprises an outer hollow shaft connectable to a universal joint and an inner hollow shaft connectable to another universal joint wherein the outer and inner hollow shafts are telescopically connected so that at least a portion of the inner hollow shaft is disposed within the outer shaft and at least a portion of the universal joints connectable to the inner shaft is disposable within the inner hollow shaft to minimize the total length of the drive line apparatus.

[0007] In another aspect of the invention, a drive line apparatus is provided for connection between an output portion of the driving member and an input portion on the driven member wherein the drive line apparatus comprises an outer hollow shaft having at least one open end and an inner hollow shaft having at least one open end. The drive line apparatus further comprises means for rotating the inner hollow shaft in unison with the outer hollow shaft. The drive line apparatus further comprises means for connecting either the inner or outer hollow shaft to the output portion of the driving member and means for connecting the other of the inner or outer hollow shaft to the input portion of the driven member, wherein at least a portion of the connection means to the inner hollow shaft is disposed within the inner hollow member.

BRIEF DESCRIPTION OF THE DRAWINGS

[0008] The description herein makes reference to the accompanying drawings wherein like reference numerals refer to like parts throughout the several views, and wherein:

[0009]FIG. 1 is an perspective view of a shaft coupling incorporating the present invention;

[0010]FIG. 2 is a cross sectional view of the shaft coupling in FIG. 1 showing an outer shaft member and inner shaft member of the shaft coupling;

[0011]FIG. 3 is an exploded view of the shaft coupling showing the outer shaft member connected to a driving member and the inner shaft member connected to a driven member; and

[0012]FIG. 4 is another exploded view from a different perspective than shown in FIG. 3 of the shaft coupling showing the inner shaft member connected to the driving member and the outer shaft member connected to the driven member.

DESCRIPTION OF THE ILLUSTRATED EMBODIMENT

[0013] Looking at the FIGS. 1-4, the drive line shaft 10 of the present invention includes a first yoke support 12, a first and second universal joint 14, 16, a second yoke support 24 and an improved shaft coupling 18 including an outer shaft member 20 and an inner shaft member 22. These components of the drive line apparatus 10 are all interconnected such that the distance between a driving member and a driven member, such as a transmission and differential or axle assembly, is maintained to a minimum.

[0014] The first and second yoke supports 12, 24, and the first and second universal joints 14, 16 are conventional devices currently used in the industry. Although many configurations are available for these devices, the Figures show just one example of devices rigidly connected to the output shaft of a driving unit, such as an engine or transmission and devices rigidly connected to the input shaft of a driven unit, such as a generator, transmission, or transfer box.

[0015] The shaft coupling 18 includes an outer shaft member 20 and an inner shaft member 22. Each of the outer and inner shaft members 20, 22 respectively, have a hollow interior. The outer shaft member 20 has an interior dimension that will receive at least a portion of the inner shaft member therein so that the outer and inner shaft members are telescopically connected. The inner shaft member 22 has an interior dimension that will receive at least a portion of one of the universal joints 12, 14 therein. The dimensions of the outer and inner shaft members 20, 22 respectively are further dependent upon the load and axial movement required for the application. In general, the outer and inner shaft members 20, 22, respectively, have a larger inner radius or areas than conventional drive line shafts.

[0016] Each of the outer and inner shaft members 20, 22 respectively have means for rigid connection to one of the universal joints 14, 16. The means for rigid connection to the universal joints is positioned on each of the outer and inner shaft members 20, 22 to minimize the space between the first and second universal joints 12, 14 while allowing for relative axial movement between the outer and inner shaft members. FIG. 3 shows one example of a means for rigid connection wherein each of the outer and inner shaft members 20, 22 have one flanged end. The flanged ends 21 and 23 of the outer and inner shaft members 20, 22 respectfully provide a surface area for connection to the universal joints 14 and 16. To ensure the connection to minimize the space between the first and second universal joints 14 and 16, the flanged ends 21 and 23 are oriented in the same direction for both outer and inner shaft members 20 and 22. That is the outer surfaces of the flanged ends 21, 23 of the outer shaft member 20 and inner shaft member 22, respectively, are oriented in the same direction such that the outer surfaces of flanged ends 21, 23 are both facing either the driving member or driven member.

[0017] The first universal joint 14 is provided for connection to the first yoke support 12 and adjacent components. The first universal joint 14 connects the outer shaft member 20 to the driving member (FIG. 3) or to the driven member (FIG. 4) via the first yoke support 12.

[0018] The second universal joint 16 may have the same configuration as the first universal joint 14. The second universal joint 16 connects the inner shaft member 22 to the driven member (FIG. 3) or to the driving member (FIG. 4) via the second yoke support 24. The yoke and universal joints shown in the Figures are only one example. Other configurations of coupling joints are known in the art.

[0019] In the illustrated embodiment, simultaneous rotation of the inner and outer shaft members is provided by splined surfaces. As seen in FIGS. 3 and 4 the inner peripheral wall of the outer shaft member 20 is splined, and the inner shaft member 22 has an outer peripheral surface which is splined. The inner shaft member has an overall diameter slightly smaller than the inner diameter of the outer shaft member 20 so that the outer splined peripheral surface of the inner shaft member 22 can be received within the inner diameter of the outer shaft member 20, and so that the splined surface of the outer shaft member 20 matingly mesh with the splined surface of the inner shaft member 22. As a result, the inner shaft member 22 rotates in unison with the outer shaft member 20.

[0020] The splined inner surface of the outer shaft member 20 and the splined outer surface of the inner shaft member 22 causes the two shaft members to rotate together and also permits the two shafts 20, 22 to move axially or endwise in relation to each other. This configuration allows changes in the length of the shaft as the rear axles move toward or away from the vehicle frame, as used in one application. The shaft coupling 18 replaces the tubular slip shafts of the prior art and allows the pair of universal joints 14, 16 to be positioned closer to each other by having the means for connection to second universal joint 16 of inner shaft member 22 moved toward the means for connection to the first universal joint 14 of the outer shaft member 20. This invention provides an advantage over the tubular slip joints of the prior art in that at least a portion of the universal joints can be encompassed within the shaft coupling 18 to minimize space required for the drive line. As seen in FIG. 2, the configuration of the preferred embodiment provides universal joint 16 to be positioned entirely within the inner shaft member 22.

[0021] Although the shaft coupling 18 has been described and shown as a cylindrical and splined device, it is apparent that other configurations are available for the shaft coupling 18. For example, the outer and inner hollow members forming the shaft coupling can be other geometric configurations. The shaft may be any three, four, or other multi-sided shaft. The inner and outer hollow members forming the shaft will have complementary surfaces which will force the inner and outer hollow members to rotate in unison.

[0022] Further, the connectors of the shaft coupling to the output of the driving member and to the input of the driven member may vary from the illustrated embodiment. Other types of universal joints, such as a simple universal joint or a two-yoke-and-spider universal joint, are conventional. The inner and outer hollow shaft members 22, 20 may also include portions of the universal joint integral with the shaft members 22, 20 for connection directly to the yokes 12, 24. 

What is claimed is:
 1. A drive line apparatus for connection between an output portion of a driving member and an input portion of a driven member, said output portion and input portion each connectable to a universal joint, said drive line apparatus comprising: a first hollow shaft connectable to a universal joint, and a second hollow shaft connectable to another universal joint, wherein at least a portion of one of the hollow shafts is disposed within the other hollow shaft and at least a portion of one of the universal joints is disposable within one of the hollow shafts.
 2. A drive line apparatus for connection between an output portion of a driving member and an input portion of a driven member, said drive line apparatus comprising: a first hollow shaft having at least one open end; a second hollow shaft having at least one open end; means for rotating said second hollow shaft in unison with the first hollow shaft; means for connecting said first hollow shaft to the output portion of the driving member; and means for connecting said second hollow shaft to the input portion of the driven member, wherein at least a portion of said means for connecting said second hollow shaft is disposed within the second hollow shaft.
 3. The drive line apparatus of claim 2 , wherein the second hollow shaft is configured and disposed coaxially within said first hollow shaft for rotational movement therewith and axial movement relative thereto.
 4. The drive line apparatus of claim 3 , wherein the means for connecting said second hollow shaft comprises at least a portion of a universal joint assembly.
 5. The drive line apparatus of claim 4 , wherein the at least a portion of the universal joint assembly is disposed within the second hollow shaft.
 6. The drive line apparatus of claim 3 , wherein the first hollow shaft has a second end with a flanged portion extending therein.
 7. The drive line apparatus of claim 6 , wherein the output portion of the driving member includes a first universal joint assembly and the input portion of the driven member includes a second universal joint assembly and wherein the means for connecting said first hollow shaft includes the first universal joint assembly connectable to the flanged portion extending into the second end of the first hollow shaft.
 8. The drive line apparatus of claim 7 , wherein the second hollow shaft has a second end with a flanged portion extending therein.
 9. The drive line apparatus of claim 8 , wherein the means for connecting said second hollow shaft includes the second universal joint assembly connectable to the flanged portion extending in the second end of the second hollow shaft.
 10. The drive line apparatus of claim 9 , wherein each flanged portion has an inner wall facing the interior of the hollow shaft and an opposing outer wall and wherein the first universal joint is connectable to the outer wall of the first hollow member and the second universal joint is connectable to the inner wall of the second hollow shaft.
 11. The drive line apparatus of claim 10 , wherein the second universal joint is disposed within the second hollow shaft when connected to the inner wall of the flanged portion of the second hollow shaft.
 12. The drive line apparatus of claim 11 , wherein the first and second hollow shafts are cylindrical.
 13. The drive line apparatus of claim 12 , wherein the first hollow shaft has an inner surface having at least one projection extending therefrom.
 14. The drive apparatus of claim 13 , wherein the second hollow shaft has an outer surface having at least one depression extending therein for receiving said at least one projection from the first hollow shaft.
 15. The drive line apparatus of claim 3 , wherein the second hollow shaft has a second end spaced from the open end and said means for connecting the second hollow shaft to the input portion of the driven member is located at the second end.
 16. A drive line apparatus for connection between an output portion of a driving member and an input portion of a driven member, said drive line apparatus comprising: a first hollow shaft; a second hollow shaft; means for connecting one of the hollow shafts to the output portion of the driving members; and means for connecting the other hollow shaft to the input portion of the driven member, wherein at least a portion of one of the hollow shafts is disposed within the other hollow shaft and at least a portion of at least one of the connecting means in connectable within one of the hollow shafts.
 17. The drive line apparatus of claim 16 , wherein the first and second hollow shafts are multi-sided and have complementary surfaces. 